Sound box for talking machines and like devices



June 9, 1931. L. A.'$MITH 1,809,493

SOUND BOX'FOR TALKING MACHINES AND LIKE DEVICES Filed July 15, 1926 K 1618 K6 K5 .k

mumumnuumuum \iu 1'. AZS LZA mven i0!" Patented June 9, 1931 warren LEO ANDREA SlViITH, OF WIIVIBLEDON, ENGLAND SOUND BOX FOR TALKING MACHINES AND LIKE DEVICES Application filed July 15, 1926, Serial No. 122,707, and in Great Britain July 25, 1925.

This invention relates to sound-boxes for talking machines, wireless loud speakers and the like.

The object of the present invention 1s to devise an improved form of sound-box of the above character and the invention consists 1n a sound-box for talking machines or like devices, in which the back of the sound-box casing has that surface adjacent to the dia- 19 phragm or other sound responsive member formed as a plurality of radially dlsposed steps which are at different distances apart from the diaphragm.

The invention also consists in other details and arrangements hereinafter described or indicated.

The accompanying drawings illustrate one convenient form of sound-box in accordance with the invention.

Figure 1 is a longitudinal sectional elevation Figure 2 is an end viewof a part of Figure 1, and

I, Figure 3 shows a perspective vlew of part of Fig. 1.

In carrying my invention into effect- 1n one convenient manner as in its application to a sound-box for talking machines, I form the sound-box casing a with diaphragm Z) en- 36 closed therein, stylus bar a and mounting therefor, in any usual or desired manner but in place of closing the back of the sound-box by means of a plain disc of ebonite or other suitable material I secure to the sound-box casing a sleeve or cylinder (Z of aluminium or other suitable metal or any other convenient material and within such sleeve or cylinder I arrange a second member 6 which is formed with or carries a part 7'' having the surface adjacent to the diaphragm formed as a series of radial steps 9 of different heights or depths as shown in Figure 1 (each of which may if desired slope slightly towards the central aperture it through which the sound Waves from the diaphragm pass). .This is suitably effected by utilizing a plurality of segments of annular form, (three being shown in the drawings) Whose adjacent ends may be made to overlap by making the three segments each longer than one third of the circumference by the amount ofvthe overlap so that radial steps are formed, suitable spacing members 9 being provided between the steps 9 and the part 7. The segments may be se cured in position by cementing them to the spacing members 9 and cementing the latter to the part f. r

I may arrangefor the stepped surface to be movable in known manner towards or away from the diaphragm, as for example the cylindrical part cl of the casing may be slidably mounted on the sleeve part e of thedevice carrying the stepped surface and a rubber ring 2' may be provided and arranged within a peripheral recess in the said part d so as to contact with the fixed part 6.

Suitable screw-operated or other means is may be adopted for the purpose of adjusting the parts in relation to one another so that the stepped surface may be moved nearer to or away from the diaphragm either during playing or when the machine is out of use and suitable means will be provided whereby the sound-box may be secured in position upon the tone arm of a talking machine.

In the construction illustrated the cylindrical part (Z is adjusted axially along the part c by means of the screw k which engages a threaded part secured to or formed with the part 03 and passes through collars 7c, 71 engaging a plate 70 secured to or formed with the member 6, said collars being held against the plate 70 by means of the lock nuts 70 k secured on the screw.

The invention is not to be limited to the foregoing details of construction which are given purely by way of illustration and not of limitation since I may form the radially stepped reflecting or like surface adjacent to the diaphragm from wood, ebonite, lead, or other material not readily responsive to sound vibrations, or the same may be formed of elastic or resilient metal, or other more resonant material than those above mentioned, and'I may modify the means adopted for adjusting the distance between such surface and the diaphragm (when such is required) depending upon any particular practical requirements that may have to be ful- 10G Having now described my invention, what I claim as new and desire to secure by Letters Patent is 1. A sound box of the kind referred to comprising a casing, a diaphragm mounted in said casing, the latter having a surface immediately adjacent to and out of parallelism with the diaphragm, said surface constituting the base of the sound box and being formed as a plurality of radial steps which are spaced at different distances from said diaphragm.

2. A sound box of the kind referred to having a casing comprising a cylindrical memher, a diaphragm mounted in said member, a sleeve mounted within said member, and a surface on said sleeve disposed immediately behind the diaphragm and formed as a plurality of radial steps spaced at different distances from and at an inclination to said diaphragm, said cylindrical member being slidably mounted on said sleeve.

3. A sound box of the type referred to comprising a casing formed of a cylindrical member, a diaphragm mounted in said casing, a sleeve mounted within said cylindrical member, a plurality of annular segments mounted on said sleeve in close proximity and immediately adjacent to the diaphragm, said segments being in overlapping relation to form a plurality of radial steps, screwoperated means for causing relative movement between said sleeve and said cylindrical member and a resilient contacting means 35 therebetween.

In testimony whereof I have signed my name to this specification.

LEO ANDREA SMITH. 

